PROJECT SUMMARY The proposed study addresses a critical knowledge gap: How to best implement digital treatments for opioids and other substance use disorders (SUDs) in primary care (PC). In 2017, the US Food and Drug Administration approved the first ever digital therapeutic for any medical condition. The therapeutic is reSET, a smartphone-based version of the Therapeutic Educational System, which is a computerized cognitive- behavioral treatment for SUDs. We will study implementation of reSET into PC to potentially improve care for people with SUDs, and as a model for how to sustainably implement digital treatments into real-world healthcare. Digital treatments could extend the reach of SUD therapy to more people and could address the lack of access to psychosocial treatment, a significant barrier to buprenorphine prescribing (a life-saving treatment for opioid use disorders [OUD]) in PC. A prior implementation trial found that a digital SUD treatment in PC was not sustained in part because of workflow and cost burdens so our study design and analytic plan focus on these issues. Our delivery system partners in Kaiser Permanente Washington are committed to collaborating with us to study strategies for implementing reSET in 25 PC clinics in Washington State and to address prior implementation challenges documented in the literature. After piloting in 2 clinics, we will randomize 23 clinics in a 2x2 factorial design to four approaches: (1) ?standard implementation,? which is an evidence-based implementation strategy previously used by our delivery system partners; (2) ?standard implementation with external facilitation,? a clinician-facing implementation strategy; (3) ?standard implementation with patient coach,? a patient-facing implementation strategy using medical assistants to support patient adoption and engagement; and (4) ?standard implementation with both.? These implementation strategies have some evidence in PC, but their impact on real-world implementation of a digital treatment has not been evaluated. Specific Aims are to (1) Estimate the effect of clinician-facing (external facilitation) and patient-facing (patient coach) implementation strategies in increasing the reach and fidelity of a digital SUD treatment in PC clinics, and (2) compare the population-level cost-effectiveness of each implementation strategy in increasing reach, fidelity, and abstinence by patients. IMPACT: Researchers and health systems do not know how to reach large numbers of patients with OUDs and other SUDs. Digital treatments are promising, but health systems lack evidence to guide implementation of digital therapies. This study will estimate and compare the effectiveness of clinician-facing and patient-facing implementation strategies, providing health system leaders with data on how to best implement digital treatments.